Adjustable ankle joint for an artificial limb



G. c. RIDDLE 2,749,557

ADJUSTABLE ANKLE JOINT FOR AN ARTIFICIAL LIMB June 12, 1956 2 Sheets-Sheet 1 Filed April 15. 1955 INVENTOR. Gr'cmf C. R/dd/e WZ PWMMW v A fzomvegs June 12, G, c RlDDLE 2,749,557

ADJUSTABLE ANKLE JOINT FOR AN ARTIFICIAL LIMB Filed ,April 15, 1955 2 Sheets-Sheet 2 I /2 i e I l i i i u I x 46 United States Patent ADJUSTABLE ANKLE JOINT FOR AN ARTIFICIAL LllVIB Grant C. Riddle, Penn, Pa. Application April 15, 1955, Serial No. 501,577 3 Claims. (Cl. 3-33) This invention relates to artificial limbs, and more particularly to adjustable joint structure for an artificial limb of the type embodying leg and foot portions connected together for relative movement and a toe element hinged to the foot portion.

A main object of the invention is to provide a novel and improved artificial limb of the type including a leg, a foot portion hinged to the leg and a toe portion hinged to the foot portion, the improved artificial limb being simple in construction, being easy to adjust, and maintaining the angular relationship of the toe portion thereof to the leg portion thereof substantially constant at all positions of adjustment.

A further object of the invention is to provide an improved artificial limb structure comprising a leg portion, a foot portion hinged to the leg portion and a toe portion hinged to the foot portion, the improved structure involving a minimum number of parts, enabling the angular position of the foot portion to be readily adjusted with respect to the leg portion of the limb, and maintaining the angular relationship of the toe portion with respect to the leg portion substantially constant at all positions of adjustment, whereby the height of the limb may be adjusted and the configuration of the foot and toe may be adjusted to conform with shoes of any predetermined heel height while keeping the calf section of the artificial limb vertical and the toe portion of the limb horizontal under all conditions of adjustment.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure l is a vertical cross sectional view taken through an improved artificial limb constructed in accordance with the present invention with the foot portion thereof shown in horizontal position.

Figure 2 is a vertical cross sectional view similar to Figure 1 showing the foot portion of the limb adjusted to its maximum downwardly inclined position.

Figure 3 is a transverse vertical cross sectional view taken on the line 3-3 of Figure 1.

Figure 4 is a diagram illustrating the angular relation- I ship of the elements of the parallel linkage defined by the limb structure in the position of Figure 1.

Figure 5 is a diagram illustrating the angular relationship of the components of the parallelogram structure defined by the artificial limb in the adjusted position of Figure 2.

Referring to the drawings, the artificial limb is designated generally at 11 and comprises a leg portion 12 to the lower end of which is secured an ankle joint member 13. Designated at 14 is a foot portion which is pivoted to the ankle joint portion 13 for rotation around a horizontal transverse axis defined by a pair of aligned horizontal studs 15, 15, as shown in Figure 3. Pivoted to the end portion of the foot element 14 is a toe portion 16, said toe portion being hinged to the end of the foot element 14 by a transverse hinge pin 17 extending through suitable overlapping hinged lugs provided on foot portion 14 and toe portion 16.

As shown in Figure 3, the leg portion 12 may include the parallel vertical wall elements 18, 18, between the lower portions of which is secured the ankle joint member 13. The foot portion 14 is provided with the upstanding pivot lugs 19, 19 between which the lower portion of the ankle joint member 13 is received. The stud elements 15, 15 are centrally secured in the rounded pivot lugs 19, 19 and are received in suitable aligned pivot recesses formed on the opposite sides of the ankle joint member 13.

Designated at 20 is an arcuate locking bar which is slidably supported in a suitably shaped arcuate recess 21 formed in the foot portion 14, said arcuate member 20 engaging cylindrical bearing elements 22 secured transversely in the bottom wall of the recess 21, whereby the member 20 may freely slide endwise in the recess 21. interposed between the ends of the arcuate bar 20 and the end walls of the recess 21 are respective rubber cushioning blocks 23, 23 which act to resiliently secure the block 20 in a centered position in the recess 21 but which at times allow said block 20 to move slightly endwise to provide a slight yielding action.

Designated at 24 is a locking rod which is slidably mounted in the ankle portion 13 and which is located centrally between the ends of the studs 15, 15, said rod 24 extending vertically, as shown in Figures 1 and 3. The top portion of the rod 24 extends through a recess 25 provided in the upper portion of the ankle joint member 13, and said ankle joint member 13 is formed with a passage 26 connecting the recess 25 to an enlarged outer recess 27 at the rear portion of the ankle joint member 13.

Designated at 28 is a lever member which is pivoted at 29 to the lower portion of the ankle joint member 13 at the lower end of recess 27, said lever 28 extending upwardly for a substantial portion of the height of said recess. The lever 28 is provided with the inwardly extending arm portion 30 which is slidably and pivotally connected at 31 to the end portion of a lever 32. The lever 32 is pivoted at its intermediate portion in the passage 26, as by a transverse pivot pin 33 extending through said passage. The inner end of the lever 32 is formed with a pair of vertical, parallel slotted fingers 34, 34 between which the rod 24 is received, said rod being provided with a transversely extending connecting pin 35 slidably engaging in the slot 36 of the fingers 34, 34.

Surrounding the rod 24 and bearing on the top edges of the fingers 34, 34 is a washer 37. A coiled spring 38 surrounds the rod 24 above washer 37 and bears between said washer and the top wall of recess 25, biasing the rod 24 downwardly toward locking engagement with a selected recess 39 provided in the top surface of the arcuate bar 20.

As shown in Figures 1 and 2, a desired number of recesses 39, for example three recesses, are spaced longitudinally along the bar 20 and the rod 24 may be engaged in any one of the recesses 39 to lock the foot portion 14 of the limb in any selected position of angular adjustment with respect to the leg portion 12.

As will be readily apparent, when the lever 28 is rotated clockwise, as viewed in Figure 1, the inner lever 32 is rotated counterclockwise, causing the rod 24 to be lifted, and freeing the foot portion 14 for angular rotation to a different adjusted position with respect to the leg portion 12. When the lever 28 is released, the spring 38 causes the rod 24 to descend into interlocking engagement with the selected locking recess 39.

Designated at 40, 40 are respective flat link bars which connect the opposite sides of the lower portion of the ankle joint member 13 to the opposite sides of the lower inner portion of the toe member 16. The bars 40 are equal in length to the distance between the pivot pin 17 and the pivot studs 15, and the pivotal connections of the ends of the link bars 40 are spaced equal distances from pivot pin 17 and the pivot studs 15, whereby a parallelogram linkage is defined, shown diagrammatically in Figures 4 and 5, wherein the reference numerals 41 and 42 designate the respective distances between the rear and forward ends of the link bars 40 from the pivot studs 15 and from the pivot pin 17. The reference numeral 43 designates the distance between the pivot studs 15 and the pivot pin 17, forming the arm of the parallelogram linkage opposite the link bars 40. As will be readily apparent from Figure 4, in the position illustrated in Figure l the toe portion 16 is subtantially perpendicular to the leg portion 12. When the foot element 14 is adjusted to the inclined position thereof of Figure 2, the toe portion 16 remains perpendicular to the leg portion 12 because of the parallelogram linkage. Thus, the toe portion 16 remains substantially horizontal regardless of the different angular adjustments of the foot portion 14 with respect to the vertical leg portion 12.

A suitable folding material 45 is provided on the opposite sides of the wall members 18, and a suitable flexible artificial skin covering 46 of suitable sheet plastic material or the like, is provided around the components of the limb. The material comprising the artificial skin covering 46 is sufiiciently flexible to allow the lever 28 to be readily manipulated, whenever it is required to elevate the locking rod 24 and to remove the rod from the locking recess 39 with which it is engaged.

While a specific embodiment of an improved artificial limb structure has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In an artificial limb comprising a leg portion, a foot portion hinged to said leg portion, and a toe portion hinged to said foot portion, means slidably mounted in said leg portion and being lockingly engageable with said foot portion to releasably secured said foot portion in an adjusted position, and means connecting said toe portion to said leg portion and being arranged to main tain a substantially constant angular relation of said toe portion to said leg portion.

2. In an artificial limb comprising a leg portion, a foot portion hinged to said leg portion, and a toe portion hinged to said foot portion, a locking rod slidably mounted in said leg portion, spaced recesses in said foot portion located to receive the end of said locking rod in different adjusted angular positions of said foot portion relative to said leg portion and arranged to releasably secure said foot portion in an adjusted position, and means connecting said too portion to said leg portion and being arranged to maintain a susbtantially constant angular relation of said toe portion to said leg portion.

3. In an artificial limb comprising a leg portion, a foot portion hinged to said leg portion, and a toe portion hinged to said foot portion, a locking rod slidably mounted in said leg portion, said foot portion being formed with spaced recesses located to receive the lower end of said locking rod in different adjusted angular positions of said foot portion relative to said leg portion and being arranged to releasably secure said foot portion in an adjusted position, and a link bar connecting said toe portion to said leg portion at points spaced substantially equal distances from the hinge connections of the foot portion and toe portion and being substantially equal in length to the distance between said hinge connections, said link bar being arranged to maintain a substantially constant angular relation of said toe portion to said leg portion.

No references cited. 

